Is your feature request related to a problem? Please describe.

Extend entity query support on Apigee entities with an option to filter them by attribute value.

Describe the solution you would like

Example.: $query->condition('attribute_value.access', 'private');

Describe alternatives you have considered

Later this feature can be extended to support filtering by other nested values as well. "." is also used a seperator in Drupal core for accessing a specific property inside a field in entity query.

Additional context